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Highlights • A novel hierarchical millisecond gas-phase catalytic cracking process was proposed. • Five catalysts were compared to study the selectivity of C 2 -C 4 hydrocarbons and BTX. • The maximum light olefins yield was obtained with 30% calcium aluminat/70% ZSM-5. • A bench-scale was used to verify the potential application of VR to chemicals. Abstract In order to enhance the production of light olefins from vacuum residue (VR), a novel hierarchical millisecond gas-phase catalytic cracking (HM-GCC) process was proposed. The process integrated the pyrolysis of VR and the catalytic cracking of the pyrolysis oil in the gas phase. Firstly, the effects of reaction temperature on the millisecond pyrolysis behavior of VR were investigated, and the results showed that the increase of C 2 -C 4 hydrocarbons content was not obvious when increasing the temperature from 600 to 750 °C. However, the thermal cracking as a pretreatment process converted the VR macromolecule into the low molecular pyrolysis oil. After that, five different catalysts calcium aluminate, FCC catalyst, and ZSM-5 zeolites (Z-40, Z-80, and Z-200) were investigated to evaluate their activities in catalytic cracking of pyrolysis oil, and among them Z-40 showed the highest selectivity for C 2 -C 4 hydrocarbons and BTX. For further study, the relative contents of C 2 -C 4 hydrocarbons were higher for the combination of calcium aluminate and Z-40 (Z + C-cat) than that of the pure Z-40 catalyst. This result was attributed to the fact that Z + C-cat facilitated the cracking of macromolecules and inhibited hydrogen transfer reactions. Finally, the conversion of VR and pyrolysis oil was studied in the bench scales with calcium aluminate and Z-40 catalyst. The yield of ethylene, propylene and butenes increased by 4.69, 7.87 and 3.37 wt% respectively in the presence of Z-40. [ABSTRACT FROM AUTHOR]

The ethylene cracking furnace system is crucial for an olefin plant. Multiple cracking furnaces are used to convert various hydrocarbon feedstocks to smaller hydrocarbon molecules, and the operational conditions of these furnaces significantly influence product yields and fuel consumption. This paper develops a multiobjective operational model for an industrial cracking furnace system that describes the operation of each furnace based on current feedstock allocations, and uses this model to optimize two important and conflicting objectives: maximization of key products yield, and minimization of the fuel consumed per unit ethylene. The model incorporates constraints related to material balance and the outlet temperature of transfer line exchanger. The self-adaptive multiobjective teaching-learning-based optimization algorithm is improved and used to solve the designed multiobjective optimization problem, obtaining a Pareto front with a diverse range of solutions. A real industrial case is investigated to illustrate the performance of the proposed model: the set of solutions returned offers a diverse range of options for possible implementation, including several solutions with both significant improvement in product yields and lower fuel consumption, compared with typical operational conditions. [ABSTRACT FROM AUTHOR]

The hydrocarbon resources of shale gas and tight oil have made a significant impact on North American energy reserves over the past decade. The production of so-called “unconventional” natural gas from U.S shales like the Barnett, Haynesville, Fayetteville, Marcellus, and Utica, and Canadian shales like the Muskwa, Montney, and Duvernay have saturated North American gas markets, boosted Canada's exports, and turned the U.S. into a net exporter of natural gas. Tight oil production from the Bakken Shale has made important contributions to the economy of the Canadian province of Saskatchewan. North Dakota has become the second largest oil producing state in the U.S. thanks to production from the Bakken. It trails only the state of Texas, which maintains first place because of equally prolific hydrocarbon liquids production from the Eagle Ford Shale and shales in the Permian basin. It is difficult to overstate the importance of these shale gas and oil resources to the U.S., North American, and world energy economies. North American shale development blossomed in the United States between 2005 and 2010, driven by high natural gas and oil prices, the availability of favorable lease positions on shale plays, and the application of drilling and stimulation technology that could successfully produce commercial quantities of hydrocarbons from these formations at economical costs. Development in Canada began a bit later, and some development has also taken place on shales in Mexico. Many people who express surprise at the apparent “overnight” success of shale gas and oil production were simply not paying attention. The truth is that a historic and protracted engineering struggle was required to identify, modify, and apply the right technology for economically-viable production. Modern assessments of the resource potential of these rocks began in the late 1970s, as did the first systematic engineering attempts to drill directional wells and hydraulically fracture shale. Success was elusive for nearly two decades, however, until the right combination of economics and technology came along. The ability of some visionary people to recognize the applications of that technology led directly to the current success of shale gas and tight oil production. Other countries considering development of their own shale resources are looking to the North American example for leadership. The success of shale resource development has not been without controversy. Public fear of the hydraulic fracturing process, or “fracking” has been amplified by shale gas opponents, leading to restrictions against shale development in many areas, and outright bans in some locations like New York and Quebec. The “boomtown” nature of the early development, and the lack of definitive environmental risk data has added to the negative perceptions, resulting in a backlash against some exploration and production ventures. Researchers have been gradually reducing the amount of uncertainty with respect to environmental risks, and as operators have gained more experience, the frequency of incidents has fallen. Many operators now recognize that obtaining a “social license” from the community is a necessary first step for successful shale gas development. [ABSTRACT FROM AUTHOR]

Additives to a zeolite-containing cracking catalyst were synthesized and studied in order to enhance the resistance to the poisoning effect of nitrogen compounds (in particular indole) upon cracking of n-undecane as the model FCC hydrocarbon. The additives were represented by acid-activated clays and mixed oxides. The activation of clays in the catalyst by 5% sulfuric acid solutions was shown to enhance the resistance to nitrogen. The introduction of Mg, Al – mixed oxides in the catalytic system in the amount of 10 wt% increased its activity and resistance to indole. The highest resistance was observed for the systems containing magnesium‑aluminum oxides with a Me 2 + to Me 3 + molar ratio equal to 0.5: 1. Cobalt modification of these mixed oxides enhanced the activity and nitrogen resistance of the cracking catalysts. Use of such nitrogen-resistant catalysts will allow cracking of heavy raw materials. [ABSTRACT FROM AUTHOR]

The effect of temperature on the cracking of pond acid tar and acid tar neutralized with lime has been studied. The formation of H2S or SO2 is determined by the amount of sulfuric acid in the tar. Liquid hydrocarbons obtained from neutralized acid tar are characterized by low sulfur content. [ABSTRACT FROM AUTHOR]

Nowadays, the time is coming for development of oil deposits with the so-called hard-to-recover reserves (HRR). Particularly relevant and important at this time are the fundamental issues of the formation of hydrocarbon deposits. To understand how the most cost-effective way to extract heavy oil from clay-bituminous sediments, it is necessary to know the nature of the process of the formation of hydrocarbons. In the present work, experimental studies confirming the influence of electromagnetic fields on the change in the fractional composition of oil and fraction of heavy naphthenic hydrocarbon fractions are considered, as well as examples of natural phenomena that could affect the rapid, jumping formation of light oil deposits by changing the electromagnetic field of our planet. The object of research is the change in the fractional composition of oil under the influence of an electromagnetic field of frequency 50 Hz and magnetic induction of about 0, 81 T, as the subject of research is oil Bazhenov horizon, which according to many scientists is oil generating in Western Siberia. The purpose of the study was to evaluate the change in heavy oil fractions under the influence of an electromagnetic field. [ABSTRACT FROM AUTHOR]

The yields of gasoline, light and vacuum gas oils, and gas fraction in thermal cracking of heavy oil residues (visbreaking) were mathematically modeled. Calculation formulas with high statistical characteristics were obtained. [ABSTRACT FROM AUTHOR]

Wilbur Nelson introduced the concept of complexity factor in the 1960s to relate the performance level of refineries with different capabilities and processing technologies. Refinery complexity has been used for many years to describe the sophistication and capital intensity of refineries, but foundational issues and the limitations associated with the metric have not been examined. A more precise and rigorous approach to complexity factors is presented based on the application of cost functions. Two alternative formulations are introduced and compared to the traditional approach and lead to new descriptive statistics and insight. [ABSTRACT FROM PUBLISHER]

Different variants of preconditioning of wet and associated petroleum gases and controlling the characteristics of the resulting fuel gases have been considered. Introduction of an additional step of preliminary oxidative conversion (prereforming) of natural and associated petroleum gases makes it possible to oxidize selectively the 'heavy' low-octane components of a complex hydrocarbon mixture and obtain fuel gas for power plants with a high methane number and a required lower heating value. Fuel characteristics of the gases obtained via partial oxidation can be further improved by admixture of gas-piston engine exhaust gas in an amount of about 100 m/1000 m to the air-fuel mixture. The version of controlling the fuel characteristics of complex gas mixtures, as described in the paper, is characterized by simplicity of engineering design, high feedstock flexibility, and the possibility to create simple-to-use modular automated systems for conditioning hydrocarbon gases in small gas fields or fields distant far from power plants. [ABSTRACT FROM AUTHOR]

The aim of this work is to study the influence of Mo on the kinetics of jatropha oil cracking on HZSM-5 catalysts, in order to select catalytic materials for the production of renewable fuels and hydrocarbons as raw chemicals for the petrochemical industry. Jatropha oil was selected as a model compound of an acidic non edible vegetable oil unsuitable for biodiesel production by conventional transesterification technology. Jatropha oil was used either pure or adsorbed on Mo/HZSM-5 surfaces. A model free kinetics was developed from non-isothermal thermogravimetric experiments of vegetable oil cracking. Fast cracking experiments were performed in a micro-pyrolysis set up, at 650 °C, under helium flow, with on line products analysis (GC/MS). Results show that the increase in the Mo content of HZSM-5 induced a decrease of both specific surface area and acidity. Mo also changed the amount and distribution of hydrocarbons obtained during cracking reactions, increasing monoaromatics and decreasing polyaromatics. TG and DTG profiles during decomposition followed by thermogravimetry indicate that the jatropha oil/catalyst mixture led to a sharp decrease in the temperature at which the main mass loss events occurred. The different values obtained for the apparent activation energy of jatropha oil decomposition suggest a different route of reaction in the presence of Mo by comparison with cracking of pure oil. [ABSTRACT FROM AUTHOR]

Catalytic and thermal cracking of polypropylene was performed in a batch reactor. Effect of hydrochloric acid activation on kaolin clay, effects of catalysts (acid-activated clays), promoter (5 wt% Ni), and cracking temperatures on the liquid oil yield were investigated. Results show optimized liquid yield (71.9%) obtained at 470°C with kaolin clay activated with 3 M HCl. Acid-activated catalysts were analyzed using XRD and the results reveal the reduction in peaks’ intensities. Weight loss of polypropylene was investigated by thermogravimetric analysis. FTIR and GCMS techniques were employed to analyze the liquid products. [ABSTRACT FROM PUBLISHER]

Disposal of waste plastic and excessive use of fossil fuels have caused environmental problems in the world. According to an estimate, more than 100 million tonnes plastics are produced every year and after their usage these plastics are discarded to become waste. Both plastic- and petroleum-derived fuels are hydrocarbons that contain the elements of carbon and hydrogen. The main difference between these hydrocarbons is that plastic molecules have longer carbon chains than those of LPG, petrol and diesel fuels. Therefore, it is possible to convert waste plastic into fuels. Pyrolysis is a prospective method to handle waste plastics. The purpose of this study is to explore the ability of different types of catalysts in conversion of plastic waste to low-emissive hydrocarbon fuel. Pyrolysis experiments were conducted using three different catalysts to check their ability in increasing the production. Catalytic degradation with potato peels yielded 74.52 wt% liquid fuel product. So far, the use of potato peels as a biocatalyst in pyrolysis process has not been reported. The pyrolysis oil was analyzed by GC/MS to determine its elemental composition. The liquid products obtained were compatible with international standards. Therefore, two main global problems such as problem of waste plastic management and problem of shortage of fuel are being tackled together. [ABSTRACT FROM PUBLISHER]

The Junggar Basin is a major oil producing province in China. Most of the oil originated from Permian lacustrine oil-prone source rocks in the basin. Kinetic parameters for oil and gas generation were obtained from confined pyrolysis experiments using gold capsules at heating rates of 20 °C/h and 2 °C/h on kerogen samples from two Permian lacustrine oil-prone source rocks (J23S3 and SS1S3) having hydrogen indices of 663 and 698 mg HC/g TOC, respectively. The kinetic properties for oil and gas generation vary substantially between these two source rocks. Assuming a burial heating rate of 5 °C/My, the temperature for 50% transformation ratio to oil is 132 °C for J23S3 and 168 °C for SS1S3. The maximum oil yields are about 604 and 770 mg/g TOC, while the maximum yields of total gaseous hydrocarbons are about 306 and 348 mg/g TOC for J23S3 and SS1S3, respectively. Gaseous hydrocarbons from the confined pyrolysis experiments include primary cracking components from kerogen and secondary cracking components from the generated oil. The secondary cracking gaseous hydrocarbons comprise up to 84.9% and 95.1% of the total, respectively, for the two source rocks in the highest temperature experiments. A practical method estimates the amount of gaseous hydrocarbons generated from these source rocks under geological conditions based on: (1) kinetic parameters for gas generation obtained from kerogen confined pyrolysis experiments in the present study, (2) the maximum yield of gaseous hydrocarbons from oil confined pyrolysis experiments from previous studies, and (3) the maximum amount of expelled oil. The maximum amounts of expelled oil range from 509–588 and 724–750 mg/g TOC with oil expulsion efficiencies in the ranges 84.3–97.4% and 94.0–97.4% for J23S3 and SS1S3, respectively, assuming that the amounts of retained oil range from 30–160 and 50–110 mg/g TOC for the two source rocks after oil expulsion based on the amounts of extracted bitumen. Consequently, the maximum yields of total gaseous hydrocarbons could be in the ranges 53.1–87.0 and 25.5–36.8 mg/g TOC, respectively, for J23S3 and SS1S3 in nature. Using the kinetic parameters for these two source rocks determined from pyrolysis experiments, oil and gas generation and expulsion were modeled for source rocks within the Lower Permian Fengcheng (P 1f ) and Middle Permian Lower Wuerhe formations (P 2w ) in the central area of the Mahu Depression, the source kitchen for most oilfields in the basin. [ABSTRACT FROM AUTHOR]

HY zeolite catalysts on montmorillonite, pillared with aluminum hydroxo complexes in different concentrations, have been tested in the cracking of heavy vacuum gas oil (VGO) from the Shymkent refinery (Kazakhstan). It has been shown that the VGO cracking activity of the catalysts is directly related to the textural and acid properties of the samples. The hydrocarbon group and fractional compositions of cracked gas-oline have been determined. [ABSTRACT FROM AUTHOR]

Calculations are performed to determine ionization potentials and wave parameters for different types of bonds, which allows the minimum time of activation of hydrocarbons containing those bonds to be calculated as well. Results are presented from a study of the effect of the parameters of electromagnetic radiation on the yields of products in the thermal cracking of non-hydrofined oil sludge. The results were used to construct the first mathematical models that make it possible to both interpolate and extrapolate the parameters of the sludge-cracking operation. [ABSTRACT FROM AUTHOR]

Hydrocarbon pyrolysis concerns many different fields (petroleum geochemistry, refinery, fuel thermal stability, pyrocarbon deposition, etc.). It is therefore studied in a wide variety of temperature–pressure experimental conditions, which strongly affect the chemistry of hydrocarbons cracking. An experimental study of the pyrolysis of n -octane has been performed at very low reactant concentration (1 mbar diluted in inert gas − total pressure 1500 mbar − molar fraction 0.07%) in a closed reactor, at temperatures ranging between 350 °C and 450 °C, and reaction time from 1 h to 70 h. The major products of the reaction are 1-alkenes (C 2 H 4 to C 7 H 14 ), methane and ethane; other alkanes (C 3 H 8 to C 6 H 14 ) are minor products. At 450 °C and 4 h, the conversion is close to 9% and we observe, in terms of molar fractions: C 2 H 4 > C 3 H 6 ≈ CH 4 > C 4 H 8 > C 5 H 10 > C 6 H 12 ≈ C 2 H 6 > C 7 H 14 These experimental results are very different from those of the thermal decomposition of n -alkanes at the same low temperature but at high pressure. In particular, the cracking stoichiometric equations (for example: C 8 H 18 = C 6 H 14 + C 2 H 4 ) are not observed since alkanes (except methane and ethane) are in very low quantities. This can be explained by the very low concentration of reactant which limits the bimolecular reactions. In our conditions, the radicals decompose several times by beta-scissions of CC bonds when it is possible (unimolecular reaction), rather than react by H-transfers (metathesis) with the reactant (bimolecular reaction) which produce alkanes. A detailed free radical mechanism (184 reactions, 16 molecules and 18 radicals— mechanism available as Supplementary material) allows modeling the experimental results. [ABSTRACT FROM AUTHOR]

This article presents a comprehensive kinetic model for thermal cracking of waste cooking oil using monomolecular lumped kinetics. The chemical lumps were classified on the basis of carbon number range of the hydrocarbons and a first order irreversible monomolecular cracking kinetics was considered for finding the product concentration in a reactor. Arrhenius kinetic law was applied for determining temperature dependency of the apparent kinetic constants included in the model. The parameter reduction was performed by calculating the preexponential factors through transition state theory and statistical thermodynamics concepts. The activation energy of the reactions was estimated through hybrid optimization using experimental data available in the literature. The proposed kinetic model for thermal cracking of waste cooking oil exhibits good agreement with the experimental data. Furthermore, the present kinetic analysis reveals that all parallel reactions from waste cooking oil are dominant for producing hydrocarbons in a product lump as compared to reactions in series and further cracking of product lumps. [ABSTRACT FROM AUTHOR]

In this paper, the cracking ability of plasma in the oil refinery, as a novel study, has been discussed. Furthermore, the cracking of n-hexadecane, lubricating oil, and heavy oil by a nonthermal plasma reactor was studied to investigate the liquid and gaseous products, gas chromatography, and simulated distillation (Sim Dis) analyzer were used. The results showed the production of hydrogen, ethane, ethylene, propane, propylene, and other hydrocarbons as a result of feedstock cracking. In these experiments, both lighter and heavier hydrocarbons were produced. In the first part, the n-hexadecane (C16H34) was injected to the reactor. The production rate of hydrogen, ethylene, and propylene were 12.74, 6.91, and 2.32 sccm, respectively. In the second part, lubricating oil, containing heavier hydrocarbons (C13–C42), was chosen as a feed. Plasma was able to crack this feed to C4–C12 with 39.77% (weight percent). In this part, the weight percent of C17+ (heavy hydrocarbons) decreased from 93.0% to 40.19%, showing that 56.8% of the heavy fraction of lubricating oil was cracked to lighter hydrocarbons. Finally, heavy oil was injected to the reactor and Sim Dis data showed that 95% of eluted materials were taken at 628 °C and 459 °C temperatures for raw and plasma treated heavy oils, showing 169 °C difference in the distribution of the boiling point of samples. This difference was due to the presence of lighter hydrocarbons with lower boiling point. [ABSTRACT FROM PUBLISHER]

The effects of high pressures on the yield and kinetics of gas generated by the cracking of crude oil were investigated in laboratory simulation experiments. Samples of a low-maturity non-marine oil were recovered from the Paleogene Shahejie Formation in the Dongying depression, Bohai Bay Basin, eastern China. The oils were cracked to gas under different pressure and temperature conditions in an autoclave. Initial temperatures of 300 °C were increased to 650 °C at rates of either 30 or 100 °C/h. Reaction products were analysed at the end of each 50 °C temperature increase. Pressure conditions were either 0.1 MPa (i.e. atmospheric) or 20 MPa. Results show that high pressures inhibit or delay oil-to-gas cracking and retard the initiation of the cracking process. The temperature at which oil was cracked and the activation energy of the formation of C1-5 hydrocarbons increased under high pressure conditions, demonstrating the effects of pressure on the kinetics of the oil-to-gas cracking process. High pressures and high temperatures inhibited the conversion of C2-5 hydrocarbons to methane during secondary cracking. In addition, high pressures retarded the generation of N2, H2 and CO during cracking of oil. The presence of water increased the yields of total cracked gas, C2-5 hydrocarbons and CO2 in high-pressure conditions. The simulation results show that CO2 and C2-5 hydrocarbons have similar yields during oil-to-gas cracking. Using the kinetic parameters determined from the laboratory experiments, the yield and production rate of gas generated during the cracking of oil from Member 4 of the Paleogene Shahejie Formation in the Minfeng-Lijin sag (Dongying depression) were calculated. The results indicate that only limited volumes of natural gas in this area were derived from the cracking of oil, and that most of the gas was derived from the thermal decomposition of kerogen. [ABSTRACT FROM AUTHOR]

The development of alternate sources of energy, particularly the use of plants as renewable sources for fuel, has received much attention recently. The potential of two indigenous arid land petrocrops,E. royleanaandE. neriifolia, as a source of hydrocarbon fuels was explored. Biocrudes extracted from these plant species were catalytically upgraded to liquid fuels using fluidized catalytic cracking. Naphtha fractions obtained by cracking of biocrudes were analyzed to give the detailed and group-wise distribution of paraffinic, isoparaffinic, oleofinic, naphthenic, and aromatic components. These naphtha fractions are similar in composition to the naphtha obtained from petroleum crudes. [ABSTRACT FROM PUBLISHER]

Highlights: [•] Coal, extracted coal and bitumen enriched coal were pyrolyzed. [•] Yields and compositions of bitumen, liquid n-alkanes and gases were determined. [•] Kinetic parameters for the generation and cracking of gas hydrocarbons were derived. [Copyright &y& Elsevier]

Highlights: [•] The understanding of antifoaming degradation is essential for silicon speciation. [•] PDMS degradation under thermal cracking of hydrocarbons was achieved. [•] Volatile siloxanes, silanes and silanol were characterized by GC/TOFMS. [•] A breakthrough in silicon speciation to understand silicon poisoning in gas cuts. [Copyright &y& Elsevier]

Abstract: A novel fixed-bed biomass gasification process (Fraunhofer ISE gasification process) for the production of tar-free synthesis gas was developed and demonstrated in a small-scale 50kW LHV (biomass) pilot plant. The process consists of four zones. Separated by moving grates to control the residence time in every zone. Thermal cracking of all higher hydrocarbons and tars occurs due to temperatures in the cracking zone of up to 1000°C, ensured via partial combustion of the raw gas. In addition, coke in the cracking zones acts catalytically. In order to increase the heating value of the product gas all remaining carbon is partially oxidized and the produced CO/CO2 is blended with the product gas. To demonstrate feasibility of the process, a pilot plant was designed, commissioned and tested. The gasifier produced a combustible gas with a lower heating value of 5.8MJ/Nm3 and CO, H2 and CH4 concentrations of 24, 14 and 2vol.%, respectively. Tar contents below 50mg/Nm3 were achieved in continuous operation. The results suggested a considerable effect of the temperature and the bed height in the tar cracking zone on the reduction of the tar content in the produced gas. [Copyright &y& Elsevier]

Abstract: Thermal pyrolysis of plastic wastes in tubular reactor has been studied with Direct Computer Mapping based simulation methodology, combined with genetic algorithm. Degradation process was carried out in laboratory and pilot scale tubular reactor. The investigated pyrolysis temperature range was 465–545°C, and raw material feeding rate was between 6 and 20g/min. A dynamic simulation model has been developed based on a four-step degradation scheme, considering four cracking product fractions (gas, naphtha, middle distillate and heavy oil) and their hydrocarbon composition (paraffin, olefin and aromatic). A collaborating genetic algorithm was used for the identification of kinetic and stoichiometric model parameters. Having analyzed the identification results we concluded that some of the stoichiometric parameters, moreover all of the kinetic parameters and vapour/liquid phase ratios were independent from the reaction parameters, however they depend on the quality of raw material. The temperature and feeding rate dependency of the model were considered by two calculated parameters (pLiq, pAro). According to the investigations, the rate determining factor of the degradation process is the effectively utilized enthalpy resulting from the heat transfer through the wall of the equipment. The simplified dynamic simulation model can support the scale-up procedure of the pyrolysis technology. [Copyright &y& Elsevier]

Abstract: Heat transfer and thermal cracking behaviors of kerosene are investigated in a thermal experiment and simulation. A flat-plane reactor of aviation kerosene with a rectangular channel is built. The heat sink and thermal cracking characteristics at subcritical and supercritical pressures are measured and compared. A one-step thermal cracking global reaction is established from the proportional product distribution and a gaseous-product experiment. The flow, heat transfer and cracking reaction of kerosene in a flat-plane reactor are coupled to simulate the two-phase flow and thermal cracking. The wall temperature predicted with a one-step thermal cracking model is in good agreement with the experimental data. The thermal cracking plays an important role in the endothermic process as the fuel temperature exceeds approximately 500°C. The rate of the variation in the overall heat sink increases with fuel temperature owing to the endothermic process of thermal cracking. An increase in pressure promotes the thermal cracking reaction. [Copyright &y& Elsevier]

Abstract: Cracking of heavy naphtha is studied experimentally in a nanosecond pulsed DBD plasma reactor. The system has been evaluated for instant production of light gaseous hydrocarbons in the range of C1–C3 and hydrogen via continuous hydrocarbons cracking at room temperature and atmospheric pressure. The effect of some process parameters such as reactor geometry/gap distance, carrier gas and feed flow rates have been considered on the reactor performance, experimentally. Results indicate that the less carrier gas and feed flow rates cause more energy efficiency. The maximum process efficiency is found for carrier gas and feed flow rates of 50 and 1ml/min, respectively, which gets higher to 106.23l/kWh for 11.50W input power and 1.35mm inner electrode diameter. Furthermore, results proof that for cracking process in DBD reactors there is an optimum diameter to maximize the process efficiency. For the reactor studied here, the optimum diameter of inner electrode is 2.68mm. In this case energy efficiency of the process is 159.29l/kWh. Results indicates that the hydrocarbon product distribution during the process is C2 >C1 ≫C3 >C4. [Copyright &y& Elsevier]

Abstract: The world energy demand is foreseen to increase due to the improvements of the living standard in the developing countries and to the development of the global economy. The increase in sustainability of the energy supply must be considered as a must to avoid spoiling the natural resources, whose availability will be crucial for next generations. The CO2-free utilization of available energy sources is one of the ways to attain such objectives. Innovative solutions should be put into practice for the CO2-free exploitation of the huge fossil fuel resources already available. In this paper we explore the possibility to enlarge the fossil fuel availability without CO2 emissions by the analysis of the technological options to obtain Hydrogen as energy carrier from hydrocarbon decarburation, mainly methane. A brief analysis of those options and a discussion about their state-of-the-art will be done, to establish their potential and the R&D required to assess their practical implementation in a medium term. [Copyright &y& Elsevier]

We have performed a direct comparison of n-hexane cracking catalysed by a zeolite (H-ZSM-5) and a heteropoly acid (phosphotungstic acid, HPW). This comparison was examined by employing density functional theory, including dispersion energy, M06-L, for the purpose of understanding these two catalysts for this industrially important reaction. The predicted adsorption energies of hexane are −21.4 and −6.8 kcal/mol for H-ZSM-5 and HPW, respectively. The protolytic cracking mechanism is proposed to proceed via the first step of the C-C activation and is found to be the rate-determining step with activation energies of 42.8 and 41.4 kcal/mol for H-ZSM-5 and HPW, respectively. We also discuss the advantages and disadvantages of both catalysts for hydrocarbon cracking and give a perspective of utilising cutting-edge molecular design for a tailor-made hybrid catalyst. © 2011 Canadian Society for Chemical Engineering [ABSTRACT FROM AUTHOR]

Modeling of complex reaction systems is necessary in the design, analysis, and optimization of many technologically important processes such as pyrolysis, steam cracking, coking, partial oxidation, and combustion. The complexity in kinetic modeling of all these processes is introduced both by the feed, which is a hydrocarbon mixture, and the high reactivity of radical intermediates. Recent advances in automated mechanism generation tools, although capable of establishing the complex reaction network, pose a big challenge of assigning rate parameters for all the reactions or devising appropriate estimation rules for all reaction classes in the network. The kinetics of free radical reactions dictates the chemistry of technologically important thermal processes. Intermolecular hydrogen abstraction by radicals is one of the dominant reaction types and constitutes a major part (often >50%) in any thermal reaction network owing to their profound effect on product distribution. While abstraction reactions by H atoms (and to some extent by methyl radicals) have been studied extensively in the past, the abstraction kinetics by vinyl radical is less explored even though vinyl radicals play an important role in molecular weight growth chemistry and in predicting acetylene concentrations in pyrolysis and fuel-rich hydrocarbon flames. This study presents the hierarchical tree structure for intermolecular hydrogen abstraction by vinyl radicals from {C/H} molecules and provides generic rate rules that account for most of the variation in CH bond energy in the family of aliphatic, aromatic, naphthenic, olefinic, and aromatic naphtheno hydrocarbons. Reaction classes developed in this work are still dictated by immediate neighbors within the spirit of group additivity, although some efforts were made to access the effect of non-next neighbors on generic rate parameters. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 327-349, 2012 [ABSTRACT FROM AUTHOR]

It is shown that axial, radial, and peripheral velocities of feed material in centrifugal vortex chamber pronouncedly differ in magnitude. The full velocity is high and attains 43 m/sec on the vortex surface. It is concluded that the cavitation region must be on the vortex surface itself, where indeed cracking of hydrocarbons intensifies. The parameters of the cavitaiton region are determined from the static liquid pressure at all points of the cavitation apparatus. The distribution of static pressure of the liquid in the centrifugal vortex chamber has a complicated pattern: the cavitation region represents a hollow truncated cone, inside which occurs a cylindrical steam vortex. Formation of a turbulent layer expands the cavitation region, the shape and size of which are calculated from the parameters of a real centrifugal chamber. [ABSTRACT FROM AUTHOR]

Sieve tray internals are a well-known method for reducing liquid phase backmixing in bubble columns. In the soaker mode of visbreaking, cracked hydrocarbon vapors increase in volume as we move up in a soaker drum because of more vapor generation due to cracking as well as reducing hydrostatic head on the gas bubbles. The free flow area in sieve trays is gradually increased as we move up in the soaker drum because of this increase in volume. A CFD analysis is presented on a soaker drum with two set of sieve tray internals with same free flow area on corresponding sieve trays, but different configuration of holes. The liquid and vapor properties have been taken identical to the hot short residue and hydrocarbon vapors, respectively. The size of flow domain for simulation has been taken equivalent to a real soaker drum, for realistic simulations. It was found that increasing of flow area in sieve trays by increasing the size of holes is more effective way for reducing liquid phase back mixing, as compared to increasing number of holes. [ABSTRACT FROM AUTHOR]

The compositions and phase conditions of water-hydrocarbon fluids in synthetic quartz inclusions were studied by the methods of microthermometry, local IR spectroscopy, and gas-liquid chromatography. Synthetic quartz was grown in near-neutral fluoride, low-alkali bicarbonate, and alkali carbonate solutions with crude oil and its major fractions. The crystals with fluid inclusions were grown under thermal gradient conditions at relatively low temperatures (240-280°C) and pressures (6-45 MPa). After the study, the inclusions of grown crystals were subject to thermal processing in autoclaves at 350-380°C and 80-125 MPa. As a result, the initial water-hydrocarbon inclusions underwent significant changes. Hydrocarbon gases, largely methane and residual solid bitumens, appeared in their composition; the gasoline-kerosene fraction content increased substantially in liquid hydrocarbons (HCs). These changes are caused, first of all, by crude oil cracking, which is manifested already at 330°C and attains its maximum activity at 350-500°C (pressure of saturated vapor and higher). In natural conditions with increase in depths and, thus, the thermobaric parameters, this process is inevitable. According to the obtained experimental data, this very phenomenon and the existence of real thermal and baric gradients in the Earth's interior provide for the formation of vertical zoning in the distribution of hydrocarbon deposits of different types. [ABSTRACT FROM AUTHOR]

Bio-oil has attracted considerable interest as a promising renewable energy resource because it can be utilized as a feedstock in integrated bio-refineries for the production of highly valuable chemicals and next-generation hydrocarbon fuels. However, it is necessary to improve the bio-oil quality before it can be fed to bio-refineries. Currently, catalytic vapor cracking seems a more attractive process than catalytic upgrading technologies, such as hydrotreating and esterification, in order to improve the bio-oil quality. This review presents a summary of recent research and the state of art technology for the catalytic vapor cracking of bio-oil, focusing on the catalysts applied, upgrading methods and reaction mechanisms. [ABSTRACT FROM AUTHOR]

The main process in oil refinery technologies is the cracking of the heavy fraction of oil into light and valuable hydrocarbons. Dielectric barrier discharge (DBD) reactors, working at atmospheric pressure and low temperature, is one of the newest methods for cracking hydrocarbons, which has been successfully used to crack low-carbon-containing molecules. Therefore, in this paper, the cracking of n-hexadecane as a heavy hydrocarbon fed by using the cylindrical DBD reactor (nonthermal plasma) has been investigated. We studied the effects of gas type, applied voltage, and gas flow rate quantitatively and qualitatively by using gas chromatography with flame ionization detector and mass spectrometry detector. Results showed that methane has better effects on both conversion and cracking percentage in comparison with air. Also, it has been shown that increasing the applied voltage and working gas flow rate enhances the conversion and the cracking percentages. The highest conversion percentage obtained was 9.26% when the applied voltage and methane flow rate were 12 kV and 50 sccm. In this condition, the cracking percentage obtained was 84.34% of the products. [ABSTRACT FROM PUBLISHER]

The author proposes a variant of modernization of the catalytic processes of deep hydrocarbon conversion. The main difference and advantage of the proposed approach and technology is that raw materials, basically heavy materials that contain great amount of different harmful mixtures, do not directly interact with the catalyst. The suggested method has a great perspective and can be easily used in the petroleum industry, and may be much cheaper than the known processes of deep conversion. The use of natural and accompanying gas, which is in many cases burned in flares, to generate atomic hydrogen or light radicals makes it possible to minimize costs of the process of deep conversion. The technology is easy to operate and does not require heavy investment and operating costs. [ABSTRACT FROM AUTHOR]

Abstract: An assessment of the process conditions for the isomerization–cracking of long-chain n-paraffins over commercial Pt/SO4 2––ZrO2 catalysts was made. Pretreatment and reaction conditions were optimized with a focus on the maximization of the yield of short, high octane branched paraffins for the gasoline pool. While selectivity was an important issue attention was also paid to the reduction of the yield to gases (C1–C4). Therefore cracking had to be modulated to produce the correct molecular size adjustment without scission to too much smaller fragments. Skeletal isomerization was to be maximized. The activity in both acid-catalyzed reactions had to be tuned while keeping a stable activity level. The only pretreatment condition assessed was the calcination temperature (screened in the 600–800°C range). Calcination at 600°C produced the highest activity level while 700°C was convenient from the point of view of selectivity. The optimum temperature coincided with the production of the highest concentration of Brönsted acid sites. Regarding the reaction conditions, increasing temperature values augmented the conversion but also increased the cracking. Therefore optimum values were found at a moderate temperature, 225°C, given the high reactivity of the feed. Space velocity values were analyzed with attention to the liquid C5+ yield, the selectivity to branched isomers and the stability of the catalysts. Best yields to branched naphtha products were obtained at WHSV=18h–1. The H2/hydrocarbon molar ratio was a function of the catalyst coking rate. A value of 10 was enough to attain a stable conversion value. The values of liquid yield as a function of pressure displayed a volcano pattern that was rationalized in terms of a non-classical bifunctional mechanism of reaction. High pressure values increased the concentration of Brönsted acid sites and hence the activity while high pressures enhanced hydrocracking and decreased the liquid yield. The optimal pressure value was 20atm. [Copyright &y& Elsevier]

Abstract: To shed light into the influences of the shape of the main hydrocarbon families constituting FCC feedstocks (naphthenes and alkanes) and of the phenolic molecules size on the MFI additive function during bio-oils and traditional Fluid Catalytic Cracking feedstocks co-processing, the transformations of n-heptane in presence of phenol and guaiacol were performed over an HMFI zeolite, at 350 and 450°C. For phenol, the results were compared with those previously obtained with methylcyclohexane. A lower impact of phenol was noticed for n-heptane than for methylcyclohexane due to the easier linear alkanes diffusion into the zeolite channels, which reveals that the phenolic molecules influence on the MFI additive function could not be as critical as envisaged for a purely naphthenic feedstock. Whatever the reactant, higher temperatures do not overcome phenol deactivating effect because, once inside the zeolite structure, phenol polar molecules diffusion is very limited. An increase of the coke molecules ramification and aromaticity was observed for the n-heptane transformation in presence of phenol, instead of a reduction of the coke production from the reactant, as noticed for methylcyclohexane. Therefore, for n-heptane the further HMFI deactivation due to phenol mainly proceeds by pore blocking, contrarily to that verified for methylcyclohexane. Furthermore, the greater the size of the phenolic molecules present in the hydrotreated bio-oils, the lower their effect on the MFI additive action. In fact, bulky oxygenated molecules are preferential adsorbed close to the zeolite outer surface, from which they are more easily removed at higher temperatures. This explains the lower guaiacol deactivating effect at 450°C, when compared with phenol. [ABSTRACT FROM AUTHOR]

Abstract: In this work the utility of new possible petrochemical feedstocks obtained by plastic waste cracking has been studied. The cracking process of polyethylene (PE), polyethylene–polypropylene (PEPP) and polyethylene-polystyrene (PEPS) has been carried out in a pilot scale tubular reactor. In this process mild reaction parameters has been applied, with the temperature of 530°C and the residence time of 15min. The produced hydrocarbon fractions as light- and middle distillates were tested by using a laboratory steam cracking unit. It was concluded that the products of the mild cracking of plastic wastes could be applied as petrochemical feedstocks. Based on the analytical data it was determined that these liquid products contained in significant concentration (25–50wt.%) of olefin hydrocarbons. Moreover the cracking of polystyrene containing raw material resulted in liquid products with significant amounts of aromatic hydrocarbons too. The steam cracking experiments proved that the products obtained by PE and PEPP cracking resulted in similar or better ethylene and propylene yields than the reference samples, however the aromatic content of PEPS products reduced the ethylene and propylene yields. [Copyright &y& Elsevier]

A new domestic catalytic cracking process with a high yield of light olefins which corresponds to the best foreign analogs with respect to the technical and economic indexes is described. This process differs from the traditional process by more severe conditions of cracking the feedstock, an increased content of ZSM-5 additive in the equilibrium catalyst, and conducting repeated cracking of light naphtha in an additional continuous reactor. [ABSTRACT FROM AUTHOR]

Abstract: A mixture of hospital post-commercial polymer waste (LDPE/HDPE/PP/PS) was pyrolyzed over various catalysts using a fluidized-bed reactor operating isothermally at ambient pressure. The yield of volatile hydrocarbons with zeolitic catalysts (ZSM-5>MOR>USY) were higher than with non-zeolitic catalysts (MCM-41>ASA). MCM-41 with large mesopores and ASA with weaker acid sites resulted in a highly olefinic product mixture with a wide carbon number distribution, whereas USY yielded a saturate–rich product mixture with a wide carbon number distribution and substantial coke levels. The systematic experiments discussed in this paper show that the use of various catalysts improves the yield of hydrocarbon products and provide better selectivity in the product distributions. A novel developed model based on kinetic and mechanistic considerations which take into account chemical reactions and catalyst deactivation for the catalytic degradation of commingled polymer waste has been investigated. This model represents the benefits of product selectivity for the chemical composition such as alkanes, alkenes, aromatics and coke in relation to the performance and the particle size selection of the catalyst used as well as the effect of the fluidizing gas and reaction temperature. [Copyright &y& Elsevier]

Abstract: Pyrolysis of industrial fatty wastes (soybean soapstock, beef tallow, and poultry industry waste) was carried out in the absence of catalysts. In all cases, organic mixtures of hydrocarbons and oxygenated compounds were obtained. These mixtures were distilled and diesel-like fractions were isolated and characterized by GC-FID, GC–MS and FT-IR, showing the formation of olefins, paraffins, and some oxygenated compounds such as carboxylic acids and esters. The main physical–chemical properties of those isolated diesel-like fuels (density, viscosity, distillation curve, carbon residue, copper corrosion test, cetane index, cold finger plugging point, acid index and heating value) were determined using ASTM standard methods and matched the Brazilian specification for diesel fuel. [Copyright &y& Elsevier]

Abstract: The Carboniferous-Permian Unayzah gas condensate reservoir of the Ghazal Field in eastern Saudi Arabia contains abundant oil inclusions indicative of a palaeo-oil column. The molecular composition of a fluid inclusion rich zone at the top of the reservoir revealed a mid-mature biomarker distribution (0.80% vitrinite reflectance equivalent, VRE) that is considerably lower than that of the co-occurring reservoired fluid (1.41% VRE). Side chain cracking of the triaromatic steroids evident in the produced condensate is significantly less advanced in the inclusion oil, as is also reflected in their alkylnaphthalene distributions. The lower maturity signal in the inclusion oil is combined with calcareous related biomarkers that include relatively abundant 30-nor-17α-hopane, C24 tetracyclic terpane and alkyldibenzothiophenes, in contrast to the reservoir hydrocarbon fluid derived from the Lower Silurian Qusaiba shale. Inclusion gas is enriched in the higher hydrocarbons, which might be attributed to a high proportion of oil (or wet gas) inclusions. Fluid inclusion ethane and propane δ 13C are very close to the mean of the produced gases, but carbon dioxide δ 13C is about 5‰, and methane δ 13C 2‰ less negative than the average of the produced Ghazal gases, which may signify more than one hydrocarbon generation/population within the fluid inclusions. An earlier contribution into the Unayzah reservoir from a non-Qusaiba source may therefore be inferred to have had preceded the volumetrically more significant and more mature Qusaiba charges. Further research is needed to elucidate the source of this oil charge and its extent, which could include deep (Cambrian or Neoproterozoic) sources that might be present in the region. [Copyright &y& Elsevier]

The presence of liquid hydrocarbon droplets in the convection section of a steam cracker may cause serious fouling problems due to coke formation, especially in high temperature zones. In order to investigate these fouling problems, a model has been developed and implemented in a CFD code to accurately simulate the behavior of a hydrocarbon droplet impinging on a hot surface. The impact energy of the droplet and the hot surface temperature are found to determine the impact behavior. On the basis of the newly developed model, the positions where droplets preferentially collide with the convection section tube walls and liquid material is deposited are determined. Furthermore, a kinetic model describing coke formation out of liquid hydrocarbon droplets in the temperature range of 450−700 K has been developed to calculate the rate of coke formation in each zone of the convection section tube. The calculated coke layer thickness on the most vulnerable tube locations and the industrially available values correspond remarkably well. [ABSTRACT FROM AUTHOR]

Cracking furnaces of ethylene plants are capable of processing multiple feeds to produce smaller hydrocarbon molecules, such as ethylene, propylene, and ethane. The best practice for handling the produced ethane is to recycle it as an internal feed and conduct the secondary cracking in a specific furnace. As cracking furnaces have to be periodically shut down for decoking, when multiple furnaces processing different feeds under various product values and manufacturing costs are considered, the operational scheduling for the entire furnace system should be optimized to achieve the best economic performance. In this paper, a new MINLP (mixed-integer nonlinear programming) model has been developed to optimize the operation of cracking furnace systems with the consideration of secondary ethane cracking. This model is more practical than the previous study and can simultaneously identify the allocation of feeds with their quantity, time, and sequence information for each cracking furnace. A case study has demonstrated the efficacy of the developed scheduling model. [ABSTRACT FROM AUTHOR]

Abstract: An ethylene plant employs multiple cracking furnaces in parallel to convert various hydrocarbon feedstocks to smaller hydrocarbon molecules, mostly ethylene and propylene. The continuous operational performance of cracking furnaces gradually decays because of coke formation in the reaction coils, which requires each furnace to be periodically shut down for decoking. Given multiple feeds and different cracking furnaces as well as various product prices and manufacturing costs, the operational scheduling for the entire furnace system should be optimized to achieve the best economic performance. In this paper, a new MINLP (mixed-integer nonlinear programming) model has been developed to obtain cyclic scheduling strategies for cracking furnace systems. Compared to previous studies, the new model has more capabilities to address operation profitability of multiple feeds cracked in multiple furnaces. Meanwhile, it inherently avoids unpractical conditions such as simultaneous shutdown of multiple furnaces. Case studies demonstrate the efficacy of the developed methodology. [Copyright &y& Elsevier]

Abstract: Pyrolysis was carried out in anhydrous closed system (gold tubes) under a constant pressure of 50MPa to discuss the differences of gas generation mechanism between crude oil and its asphaltenes. Yields and carbon isotopic composition of gaseous hydrocarbons were determined. The results show that the yield curves of gaseous hydrocarbons generated from crude oil have analogy change trends with that of asphaltenes correspondingly. The yield of methane generated from asphaltene cracking is 50% of that of oil cracking when oil and asphaltene cracked completely. The relation of δ 13C1 < δ 13C2 < δ 13C3 exists in the whole process of pyrolysis, and the δ 13C value of methane, ethane and propane generated from oil is more than that of asphaltene correspondingly. Kinetic parameters of gaseous hydrocarbon generation for crude oil and asphaltene were obtained by kinetic calculation, and the result can be extrapolated to geological conditions. [Copyright &y& Elsevier]

Abstract: The scope of the present study was to characterize the pathways leading to CH4 generation during the thermal degradation of a model compound representative of methylated monoaromatic hydrocarbons present in many crude oils. 1,2,4-trimethylbenzene was selected and subjected to pyrolysis experiments from 395 – 450°C (at 100bar). The whole range of reactant conversions was studied. All pyrolysis fractions were recovered and quantified. All products that could be quantified individually were used to develop a mechanistic kinetic model of 122 reversible reactions involving 47 species up to C18. The model was validated on our experimental results for conversions below 70%. The model was then used to assess the relative contributions of specified CH4 generation pathways at high (425°C) and low (200°C) temperatures. For the present case study, it was demonstrated that the pathways accounting for CH4 generation were the same at both temperatures. At low conversions, CH4 was mainly generated by the ‘polyaromatic route’, i.e. the dimerization of monoaromatics (step 1) followed by the intramolecular ring closure of these dimers (step 2). The contribution of the ‘monoaromatic route’, i.e. the successive demethylation reactions of methylated monoaromatics, was lower but not negligible. At higher conversions the contribution of the ‘monoaromatic route’ increased, eventually accounting for around 50% of the overall yield of CH4 at 70% conversion. Within the ‘polyaromatic route’, step 1 and step 2 quickly exhibited similar contributions, eventually sharing the remaining 50% of the overall CH4 yield at 70% conversion. [Copyright &y& Elsevier]

Abstract: The scope of the present study was to develop an empirical kinetic model predicting, over the whole range of reactant conversions (0–100%), the yield of CH4 generated from the thermal degradation of 1,2,4-trimethylbenzene, a model compound for methylated mono-aromatic hydrocarbons present in oil. Most of the chemical equations of the model were constrained by our previous mechanistic model (). The resulting reaction scheme was composed of four CH4 generation pathways: (Pa ) dimerization of 1,2,4-trimethylbenzene, (Pb ) demethylation of 1,2,4-trimethylbenzene into xylenes, (Pc ) condensation reactions of dimers and C18+ products into (prechar+char) components and (Pd ) dimerization of xylenes and their demethylation into toluene. Associated activation energies were in the range 52–61kcalmol-1 and frequency factors were all in the neighborhood of 1012 s−1. Below 5% conversion, Pb and Pc governed CH4 generation, followed by Pa . Above 5% conversion, Pc was the main source of CH4, followed by Pb and Pa , respectively. Pd showed negligible CH4 yields up to 95% conversion. Above 100% conversion, the degradation of (prechar+char) components seemed the most likely new source of gas which was not accounted for in the model. Using a unique chemical equation with a maximum CH4 yield of 7.6wt% per CH3 group and an associated set of kinetic parameters Ea =58.5kcalmol-1 and A =1011.96 s−1, we demonstrated CH4 generation kinetics from the thermal degradation of 1,2,4-trimethylbenzene to be similar to CH4 generation kinetics previously reported from the thermal degradation of methylated polyaromatic hydrocarbons. Eventually, the four-equation empirical model was used to perform simulations under temperature conditions usually encountered in deeply buried reservoirs (DBR). Under these conditions, the simulations revealed the CH4 prone character of methylated mono-aromatic hydrocarbons. Moreover, these simulations demonstrated that the thermal stability increased as follows: methylated polyaromatics